Lithium bromide

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Lithium bromide
Lithium-bromide-3D-ionic.png
Identifiers
CAS number 7550-35-8 YesY
PubChem 82050
ChemSpider 74049 YesY
UNII 864G646I84 YesY
EC number 231-439-8
RTECS number OJ5755000
Jmol-3D images Image 1
Properties
Molecular formula LiBr
Molar mass 86.845(3) g/mol
Appearance White solid
hygroscopic
Density 3.464 g/cm3
Melting point 552 °C (1,026 °F; 825 K)
Boiling point 1,265 °C (2,309 °F; 1,538 K)
Solubility in water 143 g/100 mL (0 °C)
166.7 g/100 mL (20 °C)
266 g/100 mL (100 °C)
Solubility soluble in methanol, ethanol, ether, acetone
slightly soluble in pyridine
Refractive index (nD) 1.784
Thermochemistry
Specific
heat capacity
C
51.88 J/mol K
Std molar
entropy
So298
66.9 J/mol K
Std enthalpy of
formation
ΔfHo298
-350.3 kJ/mol
Gibbs free energy ΔG -338.9 kJ/mol
Std enthalpy of
combustion
ΔcHo298
-157 kJ/mol
Hazards
EU Index Not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Not-flammable
LD50 2353 mg/kg (mouse, oral)
Related compounds
Other anions Lithium fluoride
Lithium chloride
Lithium iodide
Other cations Sodium bromide
Potassium bromide
Rubidium bromide
Caesium bromide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Lithium bromide, or LiBr, is a chemical compound of lithium and bromine. Its extreme hygroscopic character makes LiBr useful as a desiccant in certain air conditioning systems.[1]

Production and properties[edit]

LiBr is prepared by treatment of lithium carbonate with hydrobromic acid. The salt forms several crystalline hydrates, unlike the other alkali metal bromides.[2] The anhydrous salt forms cubic crystals similar to common salt (sodium chloride).

Lithium hydroxide and hydrobromic acid (aqueous solution of hydrogen bromide) will precipitate lithium bromide in the presence of water.

LiOH + HBr → LiBr + H2O

Uses[edit]

Lithium bromide is used in air-conditioning systems as desiccant.
Lithium bromide is used as a salt in absorption chilling along with water (see absorption refrigerator). Otherwise the salt is useful as a reagent in organic synthesis. For example it reversibly forms adducts with some pharmaceuticals.[1]

Medical applications[edit]

Lithium bromide was used as a sedative, beginning in the early 1900s, but it fell into disfavor in the 1940s when some heart patients died after using it as a salt substitute.[3]
Like lithium carbonate and lithium chloride, it was used as treatment for bipolar disorder.

Doses as low as 225 mg/day of LiBr can lead to bromism.

Hazards[edit]

Lithium salts are psychoactive and somewhat corrosive. When lithium bromide is dissolved into water, the reaction is very exothermic.

References[edit]

  1. ^ a b Ulrich Wietelmann, Richard J. Bauer "Lithium and Lithium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH: Weinheim.
  2. ^ Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5 
  3. ^ Bipolar disorder

External links[edit]